1. Field of the Invention
This invention relates to satellite positioning systems. More particularly it relates to a method and apparatus for determining information about the position of a satellite-positioning receiver by hypothesis validation.
2. Description of Related Art
Satellite positioning systems of various kinds are known in the art. These are also known as Global Navigation Satellite Systems (GNSS). A well known example of such a system is the Global Positioning System (GPS). Other examples include the European Union's Galileo system and the Russian system GLONASS.
These systems all work on similar principles. A uniquely identifiable signal is transmitted by each satellite, with precise synchronisation. A receiver detects signals from multiple different satellites and measures their relative times of arrival. The differences among the times of arrival correspond to the different distances from each satellite to the receiver. By establishing its relative distance from enough satellites and knowing the position of each of those satellites, the receiver is able to determine its own position by trilateration.